The author outlines what happened to the seigneury of Beauharnois after 1854 when the seigneurial system in Quebec was eliminated by the colonial government. As he explains, most seigneuries in Quebec remained a source of revenue for the seigneur, a person or organization deriving income from the land. The 1854 Act for the abolition of feudal rights and duties in Lower Canada converted the cens et rentes into constituted rents, which led to the financialization of the seigneury. This is what happened to the seigneury of Beauharnois, a valuable seigneury southwest of Montreal whose last two owners were financial institutions, namely The Montreal Investment Association and The Montreal Investment Trust. Assuming that most of the "censitaires" or tenants would not redeem the capital of their rents in order to commute the tenure of their holdings into freehold, these two companies were able to obtain substantial revenue from their seigneury until 1940, when the Quebec government definitively put an end to the constituted rents. Paradoxically, in Beauharnois this revenue was even greater after the abolition of the seigneurial system than it was before.